Files
PiAlive/node_modules/onoff/test/performance-interrupt.js
2018-05-16 10:10:23 +02:00

47 lines
1.1 KiB
JavaScript

"use strict";
/*
* In this test, GPIO7 is connected to one end of a 1kΩ current limiting
* resistor and GPIO8 is connected to the other end of the resistor. GPIO7 is
* an interrupt generating input and GPIO8 is an output. By toggling the state
* of the output an interrupt is generated. The output is toggled as often as
* possible to determine the maximum rate at which interrupts can be handled.
*/
const Gpio = require('../onoff').Gpio;
const input = new Gpio(7, 'in', 'both');
const output = new Gpio(8, 'out');
let irqCount = 0;
let iv;
// Exit handler
function exit() {
input.unexport();
output.unexport();
clearInterval(iv);
}
process.on('SIGINT', exit);
// Interrupt handler
input.watch((err, value) => {
if (err) {
exit();
}
irqCount += 1;
// Trigger next interrupt by toggling output.
output.writeSync(value === 0 ? 1 : 0);
});
// Print number of interrupts once a second.
iv = setInterval(() => {
console.log(irqCount);
irqCount = 0;
}, 1000);
// Trigger first interrupt by toggling output.
output.writeSync(output.readSync() === 0 ? 1 : 0);